The production of kilns intended for the thermal modification of wood has been traditionally carried out with machine shop methods by ordering steel plates of a given size made in stainless steel and by press-bending the same one at a time in keeping with CAD drawings for the kiln. These plates have then been assembled in the machine shop into a complete thermal modification kiln by means of a beam system, whereby the kiln can be provided with a required strength and pressure resistance, followed by shipping the kiln as a complete unit to the customer.
Due to a large size of the kiln, the transport costs in export deliveries make up a significant part of the investment costs in the case of a long distance transport. Also, many potential export countries have a lot of impediments on the road, such as bridges, traffic signs, and trees, making it difficult, if not even impossible, to transport a large complete kiln.
Because of difficulties in transport, attempts have been made to render the kilns structurally lighter or alternatively to assemble the same from components at a final destination of the kiln. Welding kiln segments together has resulted in the warping of stainless steel with a propensity of distorting structural dimensions and shapes.
Accordingly, it has been found the best practice to complete the kiln structure at a machine shop in such a way that the kiln components are first fastened together—so-called tacked—with short intermittent welds, thereby managing to assemble the entire kiln to its form. The welding together of kiln joints is not started until at this point, whereby the entire kiln is better to retain its shape and the transportation of such a constructed complete kiln is inconvenient and expensive.